Animating a series of objects along a path independently
You can add an array modifier to the object, this will allow you to control the distance from one to another. A Curve modifier will make the meshes follow the curve. You can keyframe the object to make it move along the curve.

Method 1:

Note that this will deform the object along the curve


Make sure the origin of the curve is at the start of the path.


Place the object at the start of the curve as well
Select the object. Add an Array modifier:


Count: how many copies you want
Offset: how far each object will be from one another



Add a Curve Modifier and select the curve in the Object slot.
Animate the object by setting key frames. You only need to animate the Object along one axis depending on the orientation of the curve.




Method 2:

Note: This will not deform the object along the curve. This method is a bit of a workaround and a hack.


Make sure the origin of the curve is at the start of the path.


Create a cube at the origin of the curve.
In edit mode merge all vertices into a single point. Alt M -> Center
Back in object mode add an array modifier. And set the Offset to constant.


Increase the offset to where you can see each individual point

Make sure your object is at the start of the curve
Parent the object to the array of verticies. Ctrl P
Set the Duplication type to Verts under the mesh properties. Enable Rotation.


Use the array of vertices to animate the object along the curve. Animate by setting key frames. You only need to animate the Object along one axis depending on the orientation of the curve.